The present invention relates to a device for simultaneously reinforcing a door frame and serving as an engagement surface for the bolt (e.g. latch bolt or dead bolt) of a door.
Conventional strike plates and dead bolt keepers provide a narrow latching or engagement surface which will often bend or tear when a closed door is subjected to an attack force. When the strike plate bends or tears, very little additional force on the door may be required to cause the latch bolt or dead bolt to come loose from the receptacle in the door frame located behind the strike, thereby enabling the door to be opened.
Patents of general background interest describing reinforcing means for keepers or strike plates include U.S. Pat. Nos. 2,533,396 issued Dec. 12, 1950 of Payne, 4,186,954 issued Feb. 5, 1980 of Detlefs and 4,211,422 issued Jul. 8, 1980 of Hansen. The keepers and lock strike plate assemblies of these devices require special, relatively complicated constructions. U.S. Pat. No. 4,369,994 of Vorves issued Jan. 25, 1983 describes and illustrates a strike plate support comprising a U-shaped, two-piece connection which bolts into a door frame, to circumscribe the upper, lower and outer peripheries of the receptacle for the door latch or bolt. A strike plate fits over this device and is secured to the door frame by normal wood screws. The device illustrated in this patent, in operation produces significant bending stresses on the door latch or bolt. Also, the hinge pin which joins elements forming the "U" is a point at which the unit may structurally fail is subjected to high impact forces.
Another reference of background interest is U.S. Pat. No. 3,888,530 issued Jun. 10, 1975 of Fabrici which describes and illustrates a bolt guard for a door in the form of, for example, a U-shaped plate which wraps around and sits on a door frame, and is anchored thereto. In another reference of interest, French Patent of Addition No. 56295 of Ghione granted Jul. 16, 1952, a leaf spring is mounted on the exterior of a box type lock catch, to reinforce that catch.
Other patents of general background interest are Canadian Patent No. 1,119,640 issued Mar. 9, 1982, U.S. Pat. Nos. 3,767,245 issued Oct. 23, 1973, 4,195,780 issued Apr. 1, 1980, 4,237,712 issued Dec. 9, 1980 of Cramer, 3,809,418 issued May, 1974 of Canfield, 3,936,085 issued Feb. 3, 1976 of Long, and 4,195,870 issued Apr. 1, 1980 of Percoco, U.S. Design Pat. No. Des. 263,675 issued Apr. 6, 1982 of Vorves, U.S. Pat. Nos. 4,489,968 issued Dec. 25, 1984 of Easley, 2,814,193 issued Nov. 26, 1957 of Roethel, 4,673,204 issued Jun. 16, 1987 of Allenbaugh and 4,474,394 issued Oct. 2, 1984. Many of the strike plate support assemblies of these patents have reinforcement means extending in a direction perpendicular to the door frame surface and hence perpendicular to the direction in which an attacking force to the door might be applied.